rpenmanparker 

I have been lusting after the crank set weight savings that would accompany a BB30/PF30 bottom bracket shell. Nothing wrong with my Giant TCR Advanced frame, but I was almost tempted to spring for a NOS 2011 SL ISP version with PF30. Besides the crank weight savings the whole frame would have been almost another pound lighter than my current. That would have dropped me from about 13.8 lb total bike weight (no pedals, cages, computer...) to just a bit over 12 lb. Sweet, right? Everything I have on the current bike would have transferred except the crank and BB.

Well, I have given it up. The price is potentially outstanding, pending results of the auction, but I just don't need to make the change, and I can use the money elsewhere. Anyone interested, it is here on ebay: https://www.ebay.com/itm/191020479247...84.m1438.l2648

Starting bid is only $999. That is what had caught my eye at first.

But while looking at FSA's top-of-the-line K-Force Light cranks when I was considering the new Giant frame, I saw that the older edition ones were heavily discounted on ebay, including the 386 EVO version that provides the weight savings and stiffness of an oversize Al spindle on a 68 mm threaded bottom bracket shell (or any BB shell for that matter). All I had to do in addition was get a set of 386 EVO screw-in cups and bearings. Total cost, a little over $300 (vs. around $700 list price). Weight savings about 210 g compared to the SRAM Red crank with 68 mm threaded BB I am running now. All in all, a more cost effective approach to getting the lighter crank. And when I sell the old crank, my $:g ratio for the upgrade should be just about 1:1 which I consider the benchmark for that kind of thing. Even counting selling my existing frame, I would have been out considerably more money if I bought the new frame. Just didn't need to go there.

Anyway, there are several more of these discounted cranks as well as even cheaper, lower models in different BB configurations on ebay in case you are interested. Anyone interested in my ca. 2009 SRAM Red crank and 68 mm threaded BB cups/bearings, just PM me.

RollCNY

Hi Robert!
You might want "otain" a lower case "b" as well. EBay may only have uppers.

Please imagine any others emoticons needed to insure this post is taken in the light hearted manner it is meant.

rpenmanparker 

Taken in the spirit intended. I think! Screw the "b". If "obtain" can't take a joke,...

But I do hate when I make a typo in a thread title and can't fix it. That is going to bother me until a kindly moderator fixes it for me. Billy, where are you when we need you?

kleng

Just out of interest the SRAM Red 2009 is a about 640gms, while the FSA 386 EVO (old graphic) is 554gms

The PF30 bottom bracket is around around 75gms, a Dura ace 9000 bsa bb is 68gms,

Am I missing something ? to get any significant saving you would have to install something like a THM Clavicula

I have the FSA 386 EVO crankset and the 386 EVO ceramic installed on the Litepseed L1r and it's not super light. You don't feel any additional stiffness over the Dura Ace 9000 crankset and the bb86 bottom bracket that I have in my Giant TCR Advanced Team SL 0 ISP (2011).

rpenmanparker 

Thanks for that info. My Red crank weighs in at near the published 760 g, but I forgot that is with the BB while the 553 g for the K-Force Light is, I suppose, without the BB. So it looks like the weight differential I was expecting will be shy by the weight of the BB. I will see what that is for the 386 EVO cups and bearings when I get them. Worst case, the weight savings will only 1/4 lb instead of 1/2 lb. Oh well! Live and learn. I'm still happy with the deal. I will update all the numbers when I get them. And I wasn't expecting to feel a stiffness difference. Just talking about what is advertised for the oversize spindle. I wouldn't know the difference if it bit me on the butt.

Looigi

FWIW: My '12 Red GXP crank with 34/50 rings is 576gm actual.

datlas 

Someone donated your b.

gc3

Not to jack this thread into merits of weightweenie-ism, but you are way way way too practical, my man...

....now consider the merits of a Dash post/saddle combo which can be yours for a mere $1000....

RollCNY

I have a question, or multiple questions:

I get the "I spend $300 on my current bike and save 150 grams, so that's $2/gram" math. How does it apply to new parts that you aren't upgrading, but need in the first place. I'll give my example.

Hypothetically, I am building a new bike, am partial to Deda components, and need a seatpost. So I open Ribble in a browser window and determine the following:

For $20, RS EL post is available and 277 grams.
For $50, Zero 100 post is available and 207 grams.
For $103, Super zero is available and 166 grams.

So assuming these weights are accurate, what do you do the math on?
If I go RS EL to Zero 100, I save 70 g for $30. 2.33g/$. Sweet.
If I go RS EL to Superzero, I save 111 g for $83. 1.33g/$. Not as sweet, but over 1:1.

If I go Zero 100 to Super zero, it's 41g for $53. .77g/$. Hey, that's below the sensible math.

So is there some transitive matgh global weight weenie math rule I am missing? And I know the Law of Diminishing Returns, just wonder the math answer in this hypothetical.

Edit: oops, I assumed the 10% off was everything on site, so my prices are all 10% low.

gc3

That's a trick question. It's a well known fact when it comes to new parts that you aren't upgrading, but need in the first place...there are no rules...spare no expense as long as you can pay cash and not charge it...

RollCNY

So all in but no markers. Got it.

rpenmanparker 

Your question is well stated and to the point. First the 1:1 rule is just my craziness. Depending upon your ethnicity, there are lots of other ways to say this e.g. mishegas. But it works pretty well. Second it is a lot easier to beat 1:1 on the first gram than on the last gram. So improving an already light part or whole light bike can get really pricey. So when you can cut another 1/4 lb from a light crank setup at 1:1 more or less, that's doing pretty good. No rules, just what works for you.

RollCNY

I wasn't asking to poke fun at your logic, as your are not the first with 1:1. I am back ground planning a bike build, and am deliberating those three posts. The Zero 100 looks like the sweet spot to me, but I don't know if my thought process is flawed. It is not a matter of budget, only relative worth (which I know is an entirely subjective parameter).

rpenmanparker 

Didn't really answer your question so well. Each comparison I make is a one off. I'Ve got this and want that. Or the bike come with this and I want that. Or this is on sale but I want that. What does it cost to go with the lighter choice.

datlas 

The b is gone again.

Wut